add note to tutd tutorial regarding "group" being an alternative to SQL's OUTER JOIN
commit70f13177b8127520d84a0507adde5dbf49e3010c
authorAgentM <agentm@themactionfaction.com>
dateWed 27 Sep 2017, 20:11 (9 years ago)
parentc64db99
docs/tutd_tutorial.markdown+2
@@ -282,6 +282,8 @@ The unary group operator groups the argument attributes into subrelations for ea
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283283Grouping is useful for aggregate operations (see below) or for summarizing data against a set of attributes; for example, "display all employees grouped by boss name".
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285+The group operator can also be used to emulate functionality similar to SQL's OUTER JOIN but without relying on overloading the meaning of NULL.
286+
285287```
286288TutorialD (master/main): :showexpr s group ({sname,status,s#} as subrel)
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